A massive arctic outbreak has sent most of the U.S. into a deep freeze. From the Mid-West to the Eastern Seaboard and down to the Gulf Coast, many cities are dealing with the coldest temperatures they have seen this season.
Here in New York City, the mercury fell to 8°F in Central Park this morning. Factoring in the wind chill, it felt like -8°F. Our normal low temperature for this time of year is 27°F.
As cold as it was today, it was not the coldest day the Big Apple has ever experienced. That dubious honor, according to the NWS, belongs to February 9, 1934, when the low temperature was a brutal -15°F.
Produced by a deep dip in the jet stream, our current frigid conditions are expected to stick around through the weekend. Bundle up!
The Earth reached its Perihelion today at 6:36 UTC, which is 1:36 AM Eastern Standard Time. This is the point in the planet’s orbit where it comes closest to the Sun.
This annual event is due to the elliptical shape of the Earth’s orbit and the off-centered position of the Sun inside that path. The exact date of the Perihelion differs from year to year, but it’s usually in early January – winter in the northern hemisphere. The Earth will be furthest from the Sun in July.
While the planet’s distance from the Sun is not responsible for the seasons, it does influence their length. As a function of gravity, the closer the planet is to the Sun, the faster it moves. Today, the Earth is about 146 million kilometers away from the Sun. That is approximately 5 million kilometers (3 million miles) closer than in early July. This position allows the planet to speed up by about one-kilometer/second. As a result, winter in the northern hemisphere is about five days shorter than summer.
The Holiday Season is here and many people are dreaming of a white Christmas. The likelihood of seeing those dreams come true, however, are largely dependent on where you live.
According to NOAA, a white Christmas is defined as having at least one inch of snow on the ground on December 25th. In the US, the climatological probability of having snow for Christmas is greatest across the northern tier of the country. Moving south, average temperatures increase and the chance of snow steadily decreases.
Here in New York City, the historical chance of having a white Christmas is about 12%. This low probability is largely due to the city’s proximity to the Atlantic Ocean and its moderating influence on temperature. This year, with rain and unseasonably warm temperatures in the forecast, the city’s already minimal chance for snow has largely melted away.
Snow or no snow, The Weather Gamut wishes you and your family a very Happy Holiday!
Data based on the latest (1981-2010) U.S. Climate Normals from NOAA’s National Climatic Data Center. Source: NOAA
Today is the December Solstice, the first day of winter in the northern hemisphere. The new season officially begins at 23:03 UTC, which is 6:03pm EST here in New York City.
The astronomical seasons are produced by the tilt of the Earth’s axis – a 23.5° angle – and the movement of the planet around the sun. During the winter months, the northern half of the Earth is tilted away from the sun. This position brings the hemisphere the least amount of solar energy and its coolest temperatures of the year.
Since the summer solstice in June, the arc of the sun’s daily passage across the sky has been dropping toward the southern horizon and daylight hours have been decreasing. Today, it reached its southern most position at the Tropic of Capricorn (23.5° south latitude) marking the shortest day of the year. This observable stop is where today’s event takes its name. Solstice is derived from the Latin words “sol” for sun and “sisto” for stop.
Now, the sun will move northward again in our sky and daylight hours will slowly start to increase. Marking this transition from darkness to light, the winter solstice has long been a cause for celebration across many cultures throughout human history.
Earth has seasons because it is tilted on an axis relative to its orbit around the sun. Image Credit: NASA
The Sun is directly overhead at the Tropic of Capricorn on the Winter Solstice. Image Credit: NASA
A relentless snowstorm buried the Buffalo area of western New York State with more than 5 feet of snow this week. Situated on the shore of Lake Erie, the impressive accumulation was the product of a meteorological phenomenon known as “Lake-Effect Snow.”
Lake-effect snowstorms, according to NOAA, develop when cold air blows across the warmer waters of a large unfrozen lake. The bottom layer of the air mass is warmed by the water and allows it to evaporate moisture, which forms clouds. When the air mass reaches the leeward side of the lake its temperature drops again, because the land is cooler than the water. This releases the water vapor as precipitation and enormous amounts of snow can accumulate. The effect is enhanced if the air is lifted upward by local topography.
With the clouds typically forming in bands, the snowfall is highly localized. Some places can see the snow come down at a rate of more than 5 inches per hour, while others will only get a dusting. The shape of the lake and the prevailing wind direction determines the size and orientation of these bands.
Fetch, the distance wind travels over a body of water, also plays a key role. A fetch of more than 60 miles is needed to produce lake effect snow. In general, the larger the fetch, the greater the amount of precipitation, as more moisture can be picked up by the moving air.
The massive surface area of the Great Lakes in the northern United States make them excellent producers of lake-effect snow. With northwesterly winds prevailing in the region, communities along the southeastern shores of the lakes are often referred to as being in the “Snowbelt.”
An early season arctic blast has sent temperatures across most of this country plummeting well below average this week and brought last winter’s buzzword, the polar vortex, back into the spotlight. From advertisements for winter coats to social media hashtags for almost anything cold, this technical meteorological term is being widely misused.
A polar vortex, according to NOAA, is a massive and persistent high altitude low-pressure system present over both poles of this planet. Basically a whirlpool-like wind pattern, the northern hemisphere’s polar vortex is anchored above the Arctic. It, as a whole, does not move south over the US. That said, pieces of it can ocassionally meander southward and influence our weather via the position of the polar jet stream.
When the polar vortex is strong, the jet stream generally flows in a smooth circular pattern from west to east and bottles up the Arctic’s coldest air. When weak or displaced by an area of high pressure, the shape of the jet stream distorts into a wavy, more north to south pattern. This allows cold air influenced by the polar vortex to push southward. When this happens, it is called a polar outbreak.
This week’s unseasonably cold temperatures are the result of a large ridge in the jet stream to our west that was enhanced by former typhoon Nuri in the Pacific. It, in turn, has caused a sizable trough to develop east of the Rocky Mountains and allowed cold arctic air to flow deep into the US.
In the video below, Dr. Mark Serezze, Director of the National Snow and Ice Data Center, explains exactly what the polar vortex is, how it works, and how climate change may play a role in its future.
The official start of winter is more than a month away, but New York City is experiencing an early preview.
A deep dip in the jet stream has ushered in cold arctic air and sent local temperatures plummeting. After reaching an unseasonably warm high of 65°F on Wednesday, the high in Central Park today was only 42°F. That is a difference of 23°F in just 48 hours. The city’s normal high for this time of year is 54°F.
The cold air also helped produce the city’s first snowflakes of the season. While nothing accumulated on the ground, the National Weather Service reported a trace of snow in Central Park early Friday morning. A trace of snow is defined as less than 0.1 inches.
Unlike earlier cold snaps this season, these current chilly conditions are expected to linger for at least a week.
It is now June, the first month of meteorological summer, but it seems winter is only just coming to a close on the Great Lakes.
For the first time since November, according to NOAA, the Great Lakes are ice-free. This marks the latest total thaw on the lakes since record keeping began in the 1970s. Back in March, during one of the coldest winters the region has seen in decades, more than 92% of the Great Lakes were covered by ice. That was the second highest percentage on record.
While a recent string of warm days in the area helped to melt the lingering ice, the U.S. Coast Guard also played a key role. They have reported conducting over 2000 hours of ice-breaking operations throughout this past winter and spring.
Only recently thawed, water temperatures in the lakes are expected to remain rather chilly for most of the summer.
After a frigid winter, the Great Lakes are finally ice-free. Image Credit: NOAA
Spring sprung in New York City this weekend, but winter weather came fighting back overnight. Following multiple days with temperatures in the mid-70s, many New Yorkers were surprised to find a light coating of snow on cars and sidewalks this morning.
The dramatic cool down – caused by a large mass of cold air moving in from Canada – was accompanied by rain that turned into a wintry mix overnight. With the temperature plummeting into the 30’s, the NWS issued a freeze warning for the city and surrounding area.
Snow in April is not unheard of in the Big Apple. On average the month brings us 0.6 inches. That said, as the month progresses, the chance of snow decreases. The latest measurable snowfall on record for NYC is April 25, 1875 when 3 inches accumulated in Central Park.
The winter of 2013-14 brought an exceptional amount of snowfall to New York City. In fact, it was one of our top ten snowiest.
Looking back, every month this winter, with the exception of March, was an overachiever in terms of snowfall. December brought the city 8.6 inches, January produced 19.7 inches, and February delivered an impressive 29 inches.
With a grand total of 57.4 inches of snow in Central Park, this winter was the Big Apple’s 7th snowiest on record. New York City, according to the NWS, normally gets 25.1 inches for the entire season.
In terms of temperature, NYC was cold this winter, but not in record territory. Despite numerous arctic outbreaks and the popularization of the term polar vortex, the city’s average temperature this winter season (December, January, and February) was 33°F. That is only 2°F below normal.
